The present invention relates to detection and tracking of coronary sinus catheter electrodes in fluoroscopic images, and more particularly, to detecting and tracking coronary sinus catheter electrodes in fluoroscopic images to assist in atrial fibrillation ablation procedures.
Atrial fibrillation (Afib) is a rapid, highly irregular heartbeat caused by abnormalities in the electrical signals generated by the atria of the heart. It is the most common cardiac arrhythmia (abnormal heart rhythm) and involves the two upper chambers (atria) of the heart. Afib can often be identified by taking a pulse and observing that the heartbeats do not occur at regular intervals. However, a stronger indicator of Afib is the absence of P waves on an electrocardiogram, which are normally present when there is a coordinated atrial contraction at the beginning of each heart beat. Afib may be treated with medications that either slow the heart rate or revert the heart rhythm back to normal, but this treatment may be difficult and result in complications if a patient has other diseases. Synchronized electrical cardioversion may also be used to convert Afib to a normal heart rhythm, but this technique is rarely used. Surgical and catheter-based Afib therapies, such as an ablation procedure, are also commonly used to treat Afib.
The identification of triggers that initiate Afib within the pulmonary veins (PVs) has led to prevention of Afib recurrence by catheter ablation at the site of origin of the trigger. Direct catheter ablation of the triggers was traditionally limited by the infrequency with which Afib initiation could be reproducibly triggered during a catheter ablation procedure. To overcome these limitations, an ablation approach was introduced to electrically isolate the PV myocardium. This segmental PV isolation technique involved the sequential identification and ablation of the PV ostium close to the earliest sites of activation of the PV musculature. This typically involved the delivery of radio frequency (RF) energy to 30% to 80% of the circumference of the PVs. The endpoint of this procedure was the electrical isolation of at least three PVs.
In order to construct an electrical map of the heart and assist a radiofrequency ablation operation, different catheters are inserted in a blood vessel in a patient's arm or leg and guided to the heart. The entire operation can be monitored with real-time fluoroscopic images. Tracking electrodes of the coronary sinus (CS) catheter (the catheter inside the CS) has been shown to be effective to compensate respiratory and cardiac motion for 3D overlay to assist physicians when positioning the ablation catheter. However, conventional tracking algorithms encounter difficulties in the presence of large image variations, nearby similar structures, and cluttered background.